JPS609877Y2 - Electronic desk calculator with counter - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electronic desk calculator with a counter, and more particularly to an electronic desk calculator with a counter in which a key for canceling the calculation state is also used to cancel the contents of the counter.

In conventional electronic desktop calculators with counters, for example, you press a push button on the side of the main body to accumulate the total on the counter, and use the contents as the calculation number, and the contents of the counter can be cleared. Since the clear key is also used to cancel the calculation state, separate clearing operations such as only clearing the calculation state or only erasing the contents of the counter have been impossible.

Recently, devices have been devised in which a counter is provided outside the main unit for input, but in this case, if the main unit is stored in a pocket etc., the clear key may be pressed without being noticed, and such malfunctions can be prevented. must be used without storing it in a pocket etc.

Taking the above points into consideration, the present invention relates to an electronic desktop calculator with a counter that can be used even when stored in a pocket or the like and prevents the contents of the counter from being cleared by carelessness.

FIG. 1 is a block diagram showing an embodiment of the present invention.

In the figure, 1 is a keyboard, which has numerical keys and function keys, and is a matrix type input device configured to derive key signals by introducing key scan signals from the arithmetic unit 2 of the computer. be.

C is a clear key, which instructs the calculation state of the calculation section 2 to be canceled and the counter 3 to be in the cancelable state.If the clear key C is not pressed after pressing the reset key R, the counter 3 will be reset.
The contents of are not cleared.

CO is an input part to the counter 3, for example, it is provided in a place separated from the main body and can be turned on and off manually.
Alternatively, it functions as a vibration detector in the case of a pedometer and outputs a signal when it vibrates.

The arithmetic unit 2 applies a key scan signal to the keyboard 1, detects whether or not a key is pressed by input, and executes numeric input and various arithmetic operations.

The input value or the calculation result is applied to the display path 5 via the decoder 4 and displayed on the display circuit 5.

The counter 3 counts the signal one by one when the signal from the counter input section CO is applied to the adder 6 via the lock switch SW, and normally stores the signal in circulation via the gate G without adding it.

FF is a T-type flip-flop, and the set and reset states are reversed every time a signal from the OR gate is input.
The set output Q is output to the first AND gate A1, and the reset output Q is output to the second AND gate.

The output of the first AND gate A1 is input to the OR gate OR, which inverts the flip-flop FF and inhibits the opening of the gate G to clear the contents of the counter 3.

The output of the second AND gate A2 is applied to the arithmetic unit 2, and by initializing the state of the arithmetic unit 2, the internal register contents are cleared and various conditions are reset.

The output of the counter 3 is sent to the calculation unit 2 as the output of the adder 6.
When necessary, the calculated results are switched and displayed on the display circuit 5.

When the lock switch SW is in the on state, the input section CO and the adder 6
At the same time as the input section CO is connected, the operation section 2 is made inactive, and in the OFF state, the connection between the input section CO and the adder 6 is cut off, and at the same time the operation section 2 is turned off.
, and serves both to turn on and off the calculation section 2.

Next, the operation shown in FIG. 1 will be explained using the flowchart shown in FIG.

First, when using the calculation section 2, the lock switch SW is turned off to prohibit addition to the counter 3.

In this case, the arithmetic unit 2 sends a key scan signal to the keyboard 1, detects the press of a key, and if a key is pressed, sets a number, calculates, clears, and flip-flops F according to the type of key.
An inversion of F is performed.

If no key is pressed, the display operation of the set value or result is performed.

When the reset key R is pressed, the flip-flop FF changes from reset (set) to set (reset) via the OR gate OR, and when it is in the set state, an output is generated to the decoder 4, and it is in the reset (cancellable) state. A certain thing is displayed with a special symbol on a display circuit 5.

When the clear key C is pressed in the set state, the output of the first AND gate A1 is generated, the flip-flop FF is reset, and at the same time, the gate G is shut off and the contents of the counter 3 are cleared.

When the lock switch SW is turned on, the arithmetic unit 2 becomes inactive, the key scan operation is not performed, the clear key C reset key R cannot be input, and the flip-flop FF remains in the same state.

In this state, when a pulse signal is generated from the input section CO, the adder 6 adds "1" to the contents of the counter 3.

In other words, a counting operation is performed.

Since the calculation section 2 does not operate during the counting operation, the display circuit 5
The output to the counter also disappears and no display operation is performed, but by directly giving the output of the counter 3 to the decoder 4, the contents of the counter 3 can be displayed during the counting operation.

In the above example, the state of the flip-flop FF is reversed by pressing the reset key R, but when the power switch (not shown) is turned on, it is unknown which state it is in, and it is always reset when the power is turned on. You need to make sure that it does.

For this purpose, normal initial clear operation may be used.

Further, if the contents of the counter 3 are to be held even when the power switch is turned off, the counter 3 may be constantly driven by a battery, and the arithmetic unit 2 may be turned on and off by the lock switch SW.

In this case, if battery power is constantly supplied to the display circuit 5, the display circuit 5 can display the contents of the counter 3 even when the power switch is off.

Also, in the above example, clear key C is used to clear counter 3.
However, if the arithmetic unit 2 has a spare memory register in addition to the numeric register or display register and the arithmetic register, a clear key for the memory register is provided separately from the above clear key C. Therefore, it is also possible to use the memory clear key to function as the above clear key.

Further, in the above example, if the flip-flop FF is in the set state when the clear key C is pressed, the output of the first AND gate drilling is generated, the contents of the counter 3 are erased, and the flip-flop FF is reset. F
In order to reset the flip-flop FF when a number key or a function key is pressed while F is set, another AND gate is provided which receives the set output Q of the flip-flop FF and the key signal as input, and its output is OR gated. If other output is used and the flip-flop FF is always set to the reset state when a key other than the reset key R is operated, the possibility of clearing the counter 3 by mistake is further reduced.

As mentioned above, the present invention provides an electronic desktop calculator with a built-in counter with an instruction key that instructs the counter to be in the cancelable state, and when the instruction key is in the cancelable state, the calculation content clear key is used to cancel the counter. It is used as a key, and there is no possibility of accidental erasure due to inadvertence.The contents of the counter are retained even when counting is performed while the counter is stored in a pocket, etc., and it can be erased reliably by displaying the state that it can be cleared. Can be done.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a flowchart explaining the operation of FIG. 1. In the figure, 1 is a keyboard, 2 is an arithmetic unit, 3 is a counter, 6 is an adder, SW is a lock switch, and FF is a flip-flop.

Claims (1)

[Scope of utility model registration request] An electronic desktop calculator with a built-in counter has a keyboard equipped with a switch for switching between counter mode and calculator mode, a reset key and a clear key for clearing the counter and calculator, and a keyboard key scan when the switch is in calculator mode. The present invention is characterized by comprising: an arithmetic unit for performing the above operations, a means for storing the operation state of the reset key, and a means for clearing the counter by operating the clear key when the means stores the operation state of the reset key. Electronic desk calculator with counter.